Multi-head embroidery machine

A multi-head embroidery machine comprising:

• a machine frame;
• a plurality of sewing heads mounted on said machine frame;
• each of the sewing heads including a needle bar driving mechanism for driving a needle bar, a thread take-up lever driving mechanism for driving a thread take-up lever, a presser foot driving mechanism for driving a presser foot, and a shuttle driving mechanism for driving a shuttle;
• one shuttle driving mechanism having a driving source operating independently of other driving sources for the needle bar driving mechanism, the thread take-up lever driving mechanism and the presser foot driving mechanism;
• a control device for controlling the driving source of said one shuttle driving mechanism and for controlling the driving sources of the other driving mechanisms as a function of an automatically sensed position of said one shuttle driving mechanism so that the other driving sources are simultaneously driven at predetermined timings with the driving timing of the one shuttle driving mechanism taken as a reference;
• said control device controlling the position of each thread take-up lever driven by said thread take-up lever driving mechanism as a function of at least one of several factors including the length of stitches, the material of a work to be sewn and appearance of the embroidery so that the tightness of stitches is appropriately adjusted;
• said control device controlling the position of each needle bar driven by the needle bar driving mechanism as a function of at least one of several factors including the length of the stitches, the material of a work to be sewn and the appearance of the embroidery so that the timing of the vertical movement of each needle bar is appropriately adjusted;
• and
• said control device controlling each presser foot driven by the presser foot driving mechanism in a manner wherein the presser foot vertical stroke is reduced to a minimum required length so that the acceleration at the upper dead point and the lower dead point has a minimum value.

A multi-head embroidery machine comprising:

• a machine frame;
• a plurality of sewing heads mounted on said machine frame;
• each of the sewing heads including a needle bar driving mechanism for driving a needle bar, a thread take-up lever driving mechanism for driving a thread take-up lever, a presser foot driving mechanism for driving a presser foot, a shuttle driving mechanism for driving a shuttle;
• a plurality of driving sources, one driving source for each driving mechanism;
• a first shuttle driving mechanism having a first driving source operating independently of other driving sources for the needle bar, the thread take-up lever and the presser foot driving mechanism;
• a control device for controlling the first driving source of said first shuttle driving mechanism and for controlling the driving sources of the other driving mechanisms as a function of an automatically sensed position of the first shuttle driving mechanism so that the driving sources are simultaneously driven at predetermined timings with the driving timing of the first shuttle driving mechanism taken as a reference;
• and
• said control device controlling the position of each thread take-up lever driven by the thread take-up lever driving mechanism as a function of at least one of several factors including the length of stitches, the material of a work to be sewn and the appearance of the embroidery to be obtained so that the tightness of stitches is appropriately adjusted.